Hydraulic power lift



Feh. 18, 1941. l v R D AC1-0N' l 2,232,506

HYDRAULIC POWER LIFT l* Filed Jan 19, 19:59 6 sheets-sheet 1 Inl/Q11 tor Russell?. COR

Feb. 18, 1941.

Filed Jap. 19. 1939 in u o mvg, Q 5S Nm mh 'VN E @15 di zlQ/E Oo lo r1- N1 m M/qg l M 6 Sheets-Sheet 2 @gig Feb. 18, 1941. R, Q AC1-0N 2,232,506.

HYDRAULIC P owsa LIFT Filed Jan. 19. 2959 6 Sheets-Sheet In verz for Russe BAC tol?,

Feb. 18, 1941.

n. D. AC1-0N HYDRAULIC POWER LIFT med aan. 19, 1939 CIII e l @l 78 la 6 SheetsfSheet 4f Feb. 18, 1941. R. D. AcroN HYDRAULI C POWER LI F 'I' med Jan. 19. me

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HYDRAULIC POWER L'IFT nud Jan. 19, 1939 4 6 sheets-sheet s` Izzi/@Zwar f lwsselllcon p11 1 H Patented Feb. 1a, 1941 PATENT -OFFICE HYDRAULIC POWER LIFT Russel D. A'cton, Chicago, Ill., assignor to International Harvester Company, a corporation of New Jersey Application January 19, 1939, seria1Nn.z51,1s5

16 Claims.

The present invention relates generally to power operated lifting devices 'for tractors. More specifically the invention relates to a hydraulic type of power lift mechanism.

5' The principal object of the invention is to provide a power lift device having two lifting elements which are operated consecutively to lift 20 mechanism which reverses the lifting operation and lowers the'front implement before lowering the rear implement.

The above objects and others, which will be ap- `parent from the detailed description'to follow, 5 are accomplished by mounting a hydraulic lift mechanism utilizing a vane-type piston,'such as disclosed and claimed in the Johnston Patent No. 2,039,801, May 5, 1936. By utilizing vane-type pistons in two way cylindersv generally semicylin- 39 drical in shape, the movement of thevane in one of the cylinders may be utilized to open communication with the other cylinder, whereby one of the vanes is operated subsequently to the other. By providing a suitable valve arrangement; and 35 the proper communicating conduits, the action may be reversed to return the vanes to their original position in the same order. Suitable control valve means and properly located conduits are provided for delivering the liquid under pres'- 40 sure from the pump to the proper side of the vane and for allowing the escape4 of liquid from the other side of the vane to the reservoir or low pressure side of the pump. In order to provide a mechanism in which the supply of high pressure 45 liquid is rendered ineffective after the vane has completed its stroke, valve means are utilized which are automatically operated by movement of the last vane to be operatedinto its final posi- 50 tion at the endof the stroke.

In 'the drawings:

Figure 1 is a side elevation of a tractor with one of the drive wheels removed, showing a power lift housing incorporating the invention and the 55 side of the tractor at which there is a lifting con- (oi. er1-so) nectionvwith an implement at the front of the tractor; E, e

Figure 2 is a view of the other side of the saine tractor andlifting arrangement, showing the side of the tractor at which there is a connection to an 5 implement at the rear of the tractor;

Figure 3 is a rear view of the power lift housing in its position on the frame of the tractor with certain portions broken away in section to show the vane chamber construction and the con- I struction of the controlling valve;

Figures 4 and 5 are sections taken on the line A-A of Figure 3, showing `the control valve in its two positions for lifting or for lowering;

Figure 6 is a section taken on the line B-B 15 of Figure 3 and Figure 11 with the vane in one position;

Figure 7 is a section taken on the 'line B-B of Figure 3 and Figure llvwith the vane at the end of its stroke in its other position;

Figure 8 is a section taken on the line 8-8 of Figure 3 and Figure 11;

Figures 9 and 10 are sections taken on the lines C-C of Figure 3 and Figure 11;

Figure 11 is a horizontal section taken substantially on the line II-i i of Figure 6, certain portions of the valve housing and of the shaft supporting portions of the power lift housing being shown in top plan view to better illustrate the construction thereof; and,

Figure 12 isa horizontal section taken along the line I2-I2 of Figure 10.

The tractor illustrated includes a frame l0 having laterally extending axle housings Ii, on which rear drive wheels I2 are mounted. In Figure 2, front wheels I3 are shown as well as other units of the tractor at the forward end thereof, which will not be described in detail.

At the rear of the-tractor, downwardly depending brackets I4 providemeans for connecting implement beams I extending rearwardly and carrying soir-working tools I6. Lifting links i1 connected to the beams at their lower ends are connected at' their upper ends to lifting arms I8 carried by a transverse shaft i9. Said shaft is '4 5 carried on a pair of supporting members 2 0 connected to the rear axle structures and extending rearwardly therefrom.

At the front end of the tractor, implement beams 2l, on which soll-working tools 22 are mounted, are pivotally supported on a shaft 23 carried by brackets 24 connected to the tractor. lifting levers 25, connected to the beams at their upper ends, are connected attheir upper ends to pushbaars r28.d Said bars are mounted on the ,.F'

. levers 25 to raise the rear ends of the beams 2`I on forward movement thereof andto thereby lift the front implements. The bars 26 are connected to arms 21 on a lifting rockshaft 28 mounted on brackets 29 at an intermediate point on the tractor adjacent the rear end thereof.

The power lift housing, which will be designated in its entirety by the numeral 30, is mounted on a base 3|, which is in turn mounted on the rear of the frame structure I of the tractor. Said power lift housing is made up of a section 32 provided 'with a ange 33 for mounting above the base 3l and a section 34 provided with a flange.

The section 32.,is provided with a sleeve-like hub extension 36 in which a lifting shaft 31 is journaled. At its outer end said shaft is `provided with -a crank 38, which is connected by a lifting link 39 with one of the arms 21 carried by therockshaft 28. y

The housing section 34 is formed with a sleevelike hub extension 4I, in which a lifting shaft 42 is journaled. Said shaft is provided with a lifting crank 43 connected by a link 44 witha lifting lever 45 on the rocksha'ft I9.

The housing section 32 is formed with a chamber 46 generally semicylindrical in shape, being, however, substantially more in angular extent than 180 degrees. Said chamber is open at the inner face of the housing section to provide for the insertion of the -vane 41. Said vane is mounted in a slot formed in an enlarged hub 48 formed integrally on the end of the lifting shaft 31. The vane 41 is adapted to oscillate in the chamber 46, forming a substantial liquid seal therewith. Leakage of a certain amount of liquid is not a significant feature in a device of thi-s type where an excess amount o'f fluid is being supplied by a pump having suflicient capacity to take care of any small leaks. The chamber 46 forms in effect a cylinder, and the vane 41 forms a piston oscillating therein. Insofar as the invention is concerned, the terms cylinder and piston will be used with the intention of including any other type of hydraulic device utilizing an expansible chamber and a piston operating therein.

'Ihe housing section 34 is formed with a chamber 49 identical in shape an'd size with the chamber 46. A vane 50 is mounted in the chamber in a hub carried on the lifting shaft 42. 'I'his construction is a duplication of the construction at the other side of the housing.

To complete the housing 30, the housing sections 32 and 34 are brought together with their open .ends abutting a partition or dividing member in the form of a plate 52. The entire construction is held as a unit by long cap-screws 53 extending through the housing section 32 and the plate 52 into the housing section 34.

Referring to Figure 6, it will be noted that the hub 46 of the lifting shaft l31 fits against a cylindrical surface formed by a projecting portion 54 at the bottom of the housing section to form a seal against passage of liquid from one side of the crescent-shaped chamber or compartment 46 to the other side. The lsame provision is made in the housing section 34 by a projecting portion 55 of the bottom wall of the housing section.

A hydraulic pump 56 is illustrated as being mounted at the rear of the frame structure l0 of the tractor. Said pump contains any suitable pump mechanism adapted to be operated from power derived from the tractor engine. A construction such as disclosed in the Johnston patent above referred to may be utilized as one example of a mean-s for supplying liquid under pressure.

A discharge conduit 51 leading from the pump 5 8 is connected with a conduit 58 formed in a valve body portion 59 of the housing section 34. Said conduit extends vertically upwardly, terminating in a flat face 60. A valve 6|, circular in cross-section, is mounted on the face 60, being held rotatably thereagainst by a coupling member 62 threaded on a cylindrical upper portion of the body 59. The valve 6I is provided with an operating handle 63 adapted to be engaged by an operator on the tractor for lifting and lowering the implements by means of the power lift mechanism.

As shown in Figure 4, the valve 6I is in position to ltransfer liquid under pressure delivered throughthe conduit 58 through a channel 64 formed in the valve to a conduit 65 extending vertically downwardly through the valve body portion 59 and laterally therefrom through a passage 66 in the plate 52 into a conduit 61 formed in the housing section 32. The conduit 61, as shown in Figure 11, terminates in the compartment, or cylinder'as it has been referred to, 46 beneath the vane 41 when in the position shown in Figure 6.

The operation of the power lift constituting this invention will be described along with the description of the elements and their relative arrangement. Fluid under pressure supplied beneath the vane 41 rotates said vane, the hub 48, and the lifting shaft 31 into the position in Figure 7. During this movement, the lifting crank 38 is moved from the position, as shown in Figure 1, to the dotted line position. It will be noted that both positions are past dead-center with respect tb a center line between the axis of the lifting shaft 31 and the point of connection of the link 33 with the lever 40. This type of lifting arrangement is self-locking when it 'has reached its finalposition. This feature is disclosed and claimed in the Johnston patent previously referred to. It is a particularly important feature, however, in connection with the present invention, as, when one vane has completed its lifting function, it is automatically locked in position without maintaining liquid pressure or without other locking means. This makes possible operating the second vane without giving any further consideration to the liquid pressures at opposite sides of the vane first operated.

As the vane 41 moves from the position shown in Figure 6 to the position shown in Figure '1, liquid on the low pressure side of the vane is forced out through a conduit 63 formed in the housing section 32. This conduit is shown in dotted lines in Figure 6 and in full lines in Figure 11. The conduit 68 is connected by a passage 68 in the plate 52 with -a conduit 10 formed in the section 34. Said conduit has a vertical extension terminating in the face 60, as shown in Figure 1i. With the valve in the position shown in Figure 4, liquid escaping at low pressure through the conduits 63 and 10 is transferred by a channel 1I to a return conduit 12. Said conduit has a vertical portion terminating in the face 60 and a horizontal portion, shown in Figures and 11, extending into a supply reservoir 13 formed in the housing section 34. To return liquid from the reservoir 16 to the pump 56, Aa conduit 14 is connected with the reservoir at one end with the inlet side of the pump at its other end.

The description above completes the first cycle in the lifting operation. The description will proceed with details of the valve mechanism and the conduits which operate the second vane after the first vane has completed 4*its lifting operation.

When the vane 41 reaches the position shown in Figure 1, a conduit 18, formed in the hub 48, comes into communication with a conduit 16 formed in the plate 52, as shown in Figure l1. The conduit 16 is also shown in the view of the plate 52 in Figure 8. Fluid under pressure is then supplied to the underneath side of the vane Bil in the second compartment 48 formed in the housing, section 84. The vane with the hub 5l and the shaft 42 is then rotatediinto the position shown in Figure 10.

During movement of the vane 50, liquid on the low pressure side of the vane escapes through a conduit 11 formed in the housing section 84. Said conduit extends horizontally to the 'valve portion of the housing section and then vertically terminating in the valve face 60. 'I'he channel 1i in the valve 62 previously referred to is extended to cover the outlet of the conduit 11. Fluid escaping through said conduit is transferred by the channel 1I to the conduit 12. As previously described, said conduit delivers the liquid under low pressure into the reservoir 18.

When the vane 50 has completed its cycle of movement vin the angular direction being described, the'crank 43, carried bythe shaft 42, has reved 'into position shown in Figure 2, thereby` lifting the implements at the front of the tractor. Said crank passes into a dead-center position due to angular movement of substantially more than 180 degrees of the lifting shaft 42. `'This acts to lock the implements in lifted position, thereby not requiring any hydraulic lock of the vane in its chamber. It will be noted that the crank 48 is also in a deadcenter position when the implements are in working position,.as shown by the full lines in Figure 2. This construction makes possible lthe use of spring pressureon the implements, if desired,

and prevents unlimited floating action in an upward direction. When the vane 50 reaches its position of rest,

as shown in Figure 10, a conduit 18, formed in the hub 5|, comes intoregistration with a bypass conduit 19 communicating with the reservoir 13, as shown in Figure 12. Pressure is thereby entirely releasedin the system, as thereis no substantial resistance to flow, and liquid circulated by the pump passes back into the reservoir 13. A

The'frst two steps of a complete cycle of the power lift of this invention as above describedV lifts the front implement and subsequently lifts cultivation. Another advantage is that the loadl on the lifting mechanism is divided, so that a smaller and less powerful lifting mechanism will handle a larger load by lifting a half at each step.

When the implements are to be lowered,` the valve 6i is shiftedV 90 degrees into the position shown in Figure 5'. With the valve in this position, the channel 64 forms a communication betweenthe high pressure inlet conduit B1 andthe conduit 1li leading to the underneath side of the vane 41. 'Ihe channel Il forms a by-pass communication to the reservoir between the conduit 81 continued as 6I and a conduit 80. As shown in Figure 11, the conduit 80 communicates with the chamber 49 and with the face 6I in a posi-l tionto come into registration with the extended portion of the channel 1| when the valve is in the position shown in Figure 5. It will be noted that thel conduit 80 is covered and maintained inoperative during the lifting operation. 'Ihe conduit 11, which shows-in dotted lines in Figure 5, is closed during the reverse or lowering operation.

As uid under pressure is supplied through `the conduit' 10 and the vconduit 68, the vane 41 and the elements associated therewith are rotated from the position shown in Figure '1 to the position shown in Figure 6. At the completion of the movement or stroke, 4a conduit 8|, formed in the hub 48, comes into registration with a conduit 82 formed in the plate 52, as shown in Figures 8 and 11. The high pressure fluid is then delivered to the underneath side of theA vane 50, moving it from the position shown in Figure l to the position shown in Figure 9.

During movement of the vane 41 to the position shown in Figure 6, fluid at the low pressure side of the vane flows out through the conduits 61 through the conduit 80, being transferred by the channel 1i 'to the conduit 12 `leadingl to the reservoir.

As the vane '50 comes to rest at the end of its stroke, a conduit formed-in the hub 5I comes into registration with the by-pass conduit 19, allowing the liquid being delivered by the pumpl to return to the reservoir without appreciable resistance to flow.

It will be understood that, with the reverse motions of the vanes as above described, the lifting cranks 38 and 43 'are returned to their original positions, as shown in'solid lines/in Figure l kand 2.

The double lift mechanism of applicants in- Ivention has been described as being incorporated in a hydraulic device of the'vane type as applied to a tractor for lifting implements positioned at the front and rear thereof. It is to beunderdescribed. Any type of hydraulic device is considered as coming within the scope ofthe apstood, however, that applicant does not 'limit his claim to invention to the particular construction pended claims in which, upon actuation of a valve means by anoperator, one lifting mechanism functions to complete its' cycle, at the end of which or following which a second hydraulic `mechanism is automatically brought into operation. l

Although applicant has shown a particular valve mechanism incorporated as a part-of the .hydraulic piston, any type 'of valve mechanism What is claimed is:

1. A power lift device for tractors having two 'implements mounted thereon comprising a hy-v draulically operated lifting unit connected to each implement, means for supplying liquid under putting one hydraulic mechanism into operation A following and as a result of the operation of av first mechanism.

pressure to each unit, valve means incorporated in the supply means operable for delivering liquid to one unit, and means initiated by the actuation of said unit to supply thereafter liquid under pressure to the other unit.

2. A powerlift device for tractors having two implements mounted thereon comprising a pump adapted to be driven by power derived from the tractor, a hydraulically operated lifting unit connected to each implement, means for supplying liquid under pressure from the pump to each unit, valve means incorporated in the supply means operable for delivering liquid to one unit, and means initiated by the actuation of said unit to supply thereafter liquid under pressure to the other unit.

3. A power lift device for tractors having implements mounted independently at the front and rear thereof comprising hydraulically operated lifting means independently connected to each implement, means for supplying liquid under pressure to said lifting means, valve means for delivering liquid first to the lifting means connected to the front implement, and means operable upon actuation of vsaid lifting means to supply liquid under pressure to the lifting means connected to the rear implement. 1

4. A power lift device for tractors having implements mounted independently at the front and rear thereof comprising a pump adapted to be driven by power derived from the tractor, hydraulically operated lifting means independently connected to each implement, means for supplying liquid under pressure from the pump to said lifting means, valve means for delivering liquid ilrst to the lifting means connected to the front implement, and means operable upon actuation of said lifting means to supply liquid under pressure to the lifting means connected to the rear implement.

5. A power lift device for tractors having implements mounted independently at the front and rear thereof comprising a pump adapted to be driven by power derived from the tractor, hydraulically operated lifting means independently connected to each implement, means for supplying liquid under pressure from the pump to said lifting means, valve means for delivering liquid first to the lifting means connected to the front implement, and valve means incorporated in a movable element of the lifting means operable upon completion 'of the actuation of said lifting means to by-pass the liquid under pressure to the lifting means connected to the rear implement.

6. A power lift device for tractors having two implements mounted thereon comprising a pump adaptedv to be driven by power derived from the' tractor, twov hydraulically operated cylinder and piston devices, each being independently connected to one implement, means for supplying liquid under pressure from the pump to said cylinders including valve means manually operable to deliver liquid nrst to the cylinder of one of the devices, and means initiated by the .actuation of the one 4of the devices to supply thereafter liquid under pressure to the other cylinder.

7. A power lift device for tractors having two implements mounted thereon comprising a pump adapted to be driven by power derived from the tractor, two hydraulically operated cylinder and piston devices, each being independently connected to one implement, means for supplying liquid under pressure from the pump to said cylinders including valve means operable to dell liver liquid ilrst to the cylinder of one of the devices, and means operable by completion of the stroke of the piston of said device to supply liquid under pressure to the other cylinder.

8. A power lift device for tractors having two f implements mounted thereon comprising a pump adapted to be driven by power derived from the tractor, two hydraulically operate'd cylinder and piston devices, each having independently connected to one implement, means for supplying liquid under pressure from the pump to said cylinders including valve means manually operable to deliver liquid first to the cylinder of one of the devices, and automatically operable valve means operable by completion of the stroke of the piston of said device to supply liquid under pressure to the other cylinder.

9. In a tractor having two implements mounted thereon, and a liquid pump driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted on the tractor', said casing being formed with two substantially semi-cylindrical chambers, a lifting shaft extending laterally from each lift chamber, said shafts being independently connected to the implements, a vane type piston mounted in each chamber on the lifting shaft therein, means for conducting liquid under pres-l sure from the pump to the cylinders and means for returning liquid at low pressure from the cylinders to the inlet of the pump, and valve means for first supplying liquid under pressure to one side of one vane to thereby lift one lmplement, said vane being operable at the completion of its stroke to open liquid supply means to one side of the-second vapepwhereby said vane is operated to lift the other implement at the rear of the tractor.

10. In a tractor having. a liquid pump driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted on the tractor, said casing being formed with two substantially semi-cylindrical chambers, a lifting shaft extending laterally from each lift chamber, said shafts being independently connected to the implements, a vane type piston mounted in each chamber on the lifting shaft therein, means forconducting liquid under pressure from the pump to the cylinders and means for returning liquid at low pressure from the cylinders to the inlet of the pump, and valve means for rst supplying liquid under pressure to one side of one vane to oscillate one shaft, said vane being operable at the completion of its stroke to open liquid supply means to'one side of the second vane, whereby said vane is operated to oscillate the other shaft.

1l. In a tractor having an implement mountl ed at the front thereof, yand an implement mounted at the rear thereof, and a liquid pump driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted at vthe rear of the tractor, said casing being formed with two substantially semicylindrical chambers, a lifting shaft extending laterally from each chamber, one of said shafts being connected to the implement at the front of the tractor and the other to the implement at the rear,-a vane type piston munted in each chamber on the lifting shaft therein, means for conducting liquid under pressurefrom the pump to the cylinders, means for returning liquid at low pressure from the cylinders to the inlet of the pump, and valve means for first supplying liquid under pressure to one 'side of one vane to is operated to .lift the implement at the rear of the tractor.

12. ,In a tractor having two implements mounted thereon, and a liquid pump driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted on the tractor, said casing being in two sections and being formed with semi-cylindrical chambers open at adjacent sides, a port plate between said sections, a lifting shaft extending laterally from each chamber, each of said shafts being independently'connected to an implement, a vane type piston mounted in each cylinder on the lifting shaft therein, means for conducting liquid under pressure from the pump to the chambers and means for returning liquid at lower pressure from the chambers to the inlet of the pump, and valve means for rst supplying liquid under pressure to one side of one vane to thereby lift one implement, said vane being operable at the completion of its stroke to open liquid supply means formed in the port plate to deliver under pressure to one side of the second vane, whereby said latter vane is operated to lift the other implement.

13. In a tractor having an implement mounted atthe frontthereof and an implement mounted at the rear thereof, and a liquid pump driven by power d erived from the motor, and, in combination therewith,- a hydraulic power lift casing mounted at the rear of the tractor, said casing being in two sections and being formed with semi-cylindrical chambers open at adjacent sides, a port plate between said sections, a lifting shaft extending laterally from each chamber, one of said shafts being connected to the implement at the front of the tractor and the other of said shafts being connected to the implements at the rear of vthe tractor, a vane type piston mounted in each cylinder on the lifting shaft therein,

means for conducting liquid under pressure from 'the pump to the chambers and means for returning liquid at lower pressure from the chambers to the inlet of the pump, and valve means for first supplying liquid under pressure to one side of one vane to thereby lift the implement at the front of the tractor, said vane being operable at the completion of its stroke to open liquid supply means formed in the port plate to deliver liquid under pressure to one side of the second vane, whereby said vane is operated to lift the implement at the rear of the tractor.

14. In a tractor having a liquid pump thereon' driven by power derived from the motor, and, in combination therewith, a 'hydraulic power lift casing mounted on the tractor, said casing being 4in two sections and being formed with semi-cylindrlcal fluid chambers open at adjacent sides, a port plate between said sections, a lifting shaft extending laterally from each chamber, one of said shafts being connected to the implement at the front of the tractor and the other of said shafts being connected to the implements at the rear of the tractor, a vane type piston mounted in each cylinder on the lifting shaft therein, means for conducting liquid under pressure from the pump to the chambers .and means for returning liquid at lower pressure from the chambers to the inlet of the pump, and valve means for first supplying liquid under pressure to one side of one vane, said vane being operable at the completion of its stroke to open liquid supply means formed in the port plate to deliver liquid under pressure to one side of the second vane.

15'. In a tractor having a liquid pump thereon driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted on the tractor, 4said casing being in two sections and being formed with semi-cylindrical fluid chambers open at adjacent sides, a port plate between said sections, a lifting shaft extending laterally from each chamber, one of said shafts being connected to the implement at the front-of thetractor and the other of said shafts being connected to the implements at the rear of the tractor, a vane type piston mounted in each cylinder on the lifting shaft therein, means for conducting liquid under pressure from the pump to the chambers and means for returning liquid at lower pressure from the chambers to the inlet of the pump, and valve means for first supplying liquid under pressure to one side of one vane and for draining fluid at low pressure from the other side of the vane, said'vane being operable at the completion of its stroke to open liquid supply means formed in the port plate to deliver liquid under pressure to one side of the second vane, said valve means providing for draining liquid at low pressure from the other side of said vane.

16. In a tractor having a liquid pump thereon driven by power derived from the motor, and, in combination therewith, a hydraulic power lift casing mounted on the tractor, said casing being in ltwosections and being formed with semi-cylindrical fluid chambers open at adjacent sides, a port plate between said sections, a lifting shaft extending laterally from each chamber, one of said shafts being connected to the implement at the front of the tractor and the other of said shafts being connected to the implements at the rear of the tractor, a vane type piston mounted in each cylinder on the lifting shaft therein, means for conducting liquid under pressure from the pump to the chambers and means for returning liquid at lower pressure from the cham- Vbers to the inlet of 'the pump, and valve means one side of the second vane, said valve means providing for draining liquid at low pressure from the other side of said valve, said second vane being operable upon completion of its stroke to open by-pass means to relieve pressure from the high pressure side of said vane.

RUSSEL D. ACTON.

'Patent No. 2, 252, 5o 6.

CERTIFICATE OF CORRECTION. l v

February 18, 19).;1. RUSSEL D. AcToN. It is hereby certified that errorl appears in the printed 4specification of the above numbered patent requiring correctionas follows: Page li, seciond column, line 8, claim 8, for the word havin-g" read --being--yand that the said Letters Patent should be read with this correction therein that the same may conform to the record of the oase in the Patent Office.

signed and sealed this 1st day of Apr-11, A. D. 1914i..

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

